JPWO2014171537A1 - Intraocular lens - Google Patents

Abstract

Provided is a technique for suppressing the rotation of an intraocular lens disposed in an eyeball as a lens replacing a crystalline lens after the lens is disposed. The intraocular lens having a lens body 10a that functions as a lens and a pair of support portions 10b that support the lens body 10a in the eyeball. Of the support portions 10b of the intraocular lens 10, the lens of the intraocular lens 10 A support point 10d having a maximum radial distance from the center O of the main body 10a, a connection point 10c at which the support portion 10b and the lens main body 10a are combined, and a center O of the lens main body 10a are substantially the same. It is configured to line up in a straight line.

Description

  The present invention relates to an intraocular lens that is inserted into the eye and placed in the lens capsule as a lens that replaces the lens after removing and removing the lens in the lens capsule from the eyeball in an operation such as cataract.

  Cataract is an aging phenomenon that appears with aging, and is a disease in which the lens becomes cloudy and the visual acuity decreases. As a treatment method, after removing and removing the crystalline lens, a method of inserting a lens that replaces the crystalline lens, that is, an intraocular lens is generally used. When inserting an intraocular lens, an incision is made in the eye tissue such as the cornea (capsular membrane) or anterior lens capsule in the eyeball, and the lens in the lens capsule is removed and removed through this incision. As an alternative to the lens, an intraocular lens is inserted into the eye through the incision and placed in the lens capsule.

  In general, cataract surgery is performed in the following steps. (1) Incising the cornea or cornea on the ear side or above the pupil. (2) Inject a viscoelastic substance such as hyaluronic acid to protect the organs in the eyeball. (3) Insert an instrument from the above incision to make a circular hole in the anterior capsule of the lens, and remove the lens from the hole. (4) The intraocular lens is inserted through the incision using the dedicated insertion instrument. (5) Adjust the astigmatism axis. (6) Remove the viscoelastic material.

  As described above, since the intraocular lens is a lens that replaces the crystalline lens, it is desirable to replace and further compensate for the optical performance of the crystalline lens. As the optical performance to be compensated by the intraocular lens, optical power, multifocality, astigmatism and the like can be considered.

  Another example of biological information to be considered is that the astigmatism axis is different for each patient. That is, in cases with corneal astigmatism, an astigmatic intraocular lens called a toric intraocular lens is used, and when inserting this intraocular lens, the direction of the astigmatic axis of the cornea and the direction of the toric axis of the intraocular lens It is necessary to match. In this regard, in the step (4), the orientation of the intraocular lens is generally determined with respect to the insertion instrument, and when it is inserted into the eyeball, it is oriented in a certain direction. Therefore, in order to match the direction of the astigmatic axis of the cornea with the direction of the toric axis of the intraocular lens, the direction of the toric axis must be adjusted by rotating the intraocular lens after inserting the intraocular lens into the eyeball. Don't be.

  When inserting an intraocular lens, not only align the astigmatic axis direction of the cornea with the toric axis direction of the intraocular lens at the time of insertion, but also rotate the intraocular lens within the capsular bag after the operation. It is necessary to prevent the directions of both axes from shifting. In particular, after the intraocular lens is inserted into the eyeball, the intraocular lens is not sufficiently fixed by the capsular bag until the capsular bag is completely contracted. Actually, since cataract surgery is often performed as a day surgery, there is a case in which some force acts on the intraocular lens in the course of normal life and the direction of the toric axis of the intraocular lens is shifted.

  On the other hand, in order to suppress the rotation of the intraocular lens after insertion into the eyeball, the tip of the support part of the intraocular lens is formed in a saw-tooth shape to increase the resistance to the rotation of the intraocular lens in the lens capsule. Is also considered. However, in such a method, there is a risk that the capsular bag itself is damaged by the saw-shaped support portion. In addition, as a countermeasure against the rotation of the intraocular lens, it may be possible to reduce the sensitivity of the resolving power to the rotation of the lens, but in this case, the peak resolving power itself is sacrificed and the performance of the intraocular lens is degraded. There was inconvenience that it led to.

German Patent Application Publication No. 10202679 European Patent Application No. 1591080 International Publication No. 01/60286 Pamphlet

  The present invention has been devised in view of the above-described problems of the prior art, and an object of the present invention is that an intraocular lens arranged in an eyeball as a lens replacing a crystalline lens rotates after the arrangement. It is to provide a technique for suppressing the problem.

  The present invention for solving the above technical problem relates to an intraocular lens having an optical part that functions as a lens and a pair of support parts that support the optical part in the eyeball, and the support part of the intraocular lens. Of these, the support point, which is the maximum radial distance from the center of the optical part of the intraocular lens, the connection point where the support part and the optical part are combined, and the center of the optical part are approximately The biggest feature is that it is arranged in a straight line.

More specifically, an optical unit having optical performance that can replace the crystalline lens in the eyeball,
A plurality of support portions provided in a form extending on the outer peripheral side of the optical portion and supporting the optical portion within the eyeball,
An intraocular lens inserted into an eyeball by an insertion device from an incision formed in the eyeball,
In the state where the intraocular lens is inserted into the lens capsule, a support point that is the point having the maximum radial distance from the center of the optical unit in the support unit, and the support unit and the optical unit are combined. The coupling point and the center of the optical part are arranged in a substantially straight line.

  As a cause of the rotation of the intraocular lens after the intraocular lens is inserted and arranged in the eyeball, the lens capsule accommodated after the intraocular lens is inserted is contracted for focus adjustment. In doing so, it has become clear that the elastic contraction force acting on the coupling point between the support part and the optical part is involved. That is, when the lens capsule contracts for focus adjustment, the ciliary muscle is tense and the lens capsule is in contact with the support (the radial distance from the center of the optical section is the maximum). The elastic contraction force acts on the support point which is a point. And this elastic contraction force acts on the connection point of a support part and an optical part via a support part. Furthermore, it is considered that a moment is generated by a component in the circumferential direction of the optical part among the elastic contraction force acting on the coupling point, and the optical part of the intraocular lens is rotated.

  Further, the circumferential component of the elastic contraction force acting on the coupling point (the component in the rotational direction of the intraocular lens) is a straight line connecting the support point in the support unit and the center of the optical unit, and the support unit and the optical unit. It has become clear that the angle between the coupling point and the straight line connecting the center of the optical part becomes relatively larger as the angle approaches 90 degrees. On the other hand, when the support point, the coupling point, and the center of the optical part are arranged in a substantially straight line (for example, a straight line connecting the support point in the support part and the center of the optical part, When the angle formed by the connecting point between the support part and the optical part and the straight line connecting the center of the optical part is close to 0 degrees or 180 degrees), the circumferential component of the elastic contraction force acting on the connecting point is It has been found that it approaches zero.

  Therefore, in the present invention, as the configuration of the intraocular lens, the support point, the coupling point, and the center of the optical unit are arranged in a substantially straight line with the intraocular lens inserted into the lens capsule. To be configured. Thereby, the component of the direction which rotates an optical part among the elastic contraction force which acts on a coupling | bond part when a lens capsule shrink | contracts for focus adjustment can be made close to zero. As a result, rotation of the intraocular lens after being inserted into the eyeball can be suppressed.

  In the present invention, the support portion may have no inflection point in a range from the coupling point to the support point in a state where the intraocular lens is inserted into the lens capsule.

  Here, consider a case where the support portion has an inflection point in the range from the coupling point to the support point in a state where the intraocular lens is inserted into the lens capsule. In such a case, the support part often has a shape that is folded on the outer periphery of the optical part. Then, the shape of the support part becomes complicated, and even if the support point that is the point where the radial distance from the center of the optical part is the maximum is clearly defined in the support part, only this support point is perpendicular to the lens optical axis. It is likely to be unclear whether or not is actually in contact with the eyeball tissue of the lens capsule. That is, for example, it is conceivable that a wide area in the support portion or a plurality of points in the support portion contact the lens capsule. Then, the location where the elastic contraction force acts on the support portion and the direction of the elastic contraction force acting become unclear, and as a result, the direction and magnitude of the elastic contraction force acting on the coupling point can be specified and controlled. It becomes difficult.

  On the other hand, in the present invention, in the state where the intraocular lens is inserted into the crystalline lens capsule, the support portion does not have an inflection point in the range from the coupling point to the support point. The shape of the support portion can be simplified between the connection points, and more easily, only the support points can come into contact with the eyeball tissue of the lens capsule. As a result, the support point, the coupling point, and the center of the optical unit can be more easily arranged in a substantially straight line. As a result, even if the lens capsule contracts, it becomes possible to make it difficult for the elastic contraction force in the direction of rotating the optical section to act on the coupling section.

  Further, in the present invention, an angle formed by a straight line connecting the support point and the center of the optical unit and a straight line connecting the coupling point and the center of the optical unit is such that the intraocular lens is inserted into the lens capsule. In this state, it may be 14.4 degrees or less.

  Here, as described above, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the connection point and the center of the optical unit is smaller in the range of 90 degrees or less. The circumferential component of the elastic contraction force acting on the point (the component in the rotational direction of the intraocular lens) can be reduced. On the other hand, in order to prevent the intraocular lens from actually rotating in the eyeball, a rotational force larger than the rotational resistance force of the intraocular lens in the eyeball may be prevented from acting. Then, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is not necessarily zero (in this case, the support point, the coupling point, and the center of the optical unit). Are not necessarily aligned on a straight line). The condition can be satisfied if the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is equal to or less than a predetermined threshold.

  According to the inventor's earnest research, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is such that the intraocular lens is in the lens capsule. It has been found that if it is at least 14.4 degrees or less in the inserted state, it is possible to create a situation where the intraocular lens is very difficult to rotate within the eyeball. Therefore, in the present invention, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit may be 14.4 degrees or less. If it does so, it can suppress more reliably that an intraocular lens rotates in an eyeball after insertion.

  In the present invention, each of the plurality of support units may be coupled to the optical unit only at the coupling point.

  Here, the support part of the intraocular lens is of a type that is coupled with the optical part at another place other than the joint part in addition to the support part that is coupled with the optical part at one place only at the joint part. There is a support part. In the present invention, when a support portion of a type that forms a loop is used as the support portion, the elastic contraction force acting on the support point due to the contraction of the lens capsule acts on the optical portion at a plurality of points via the support portion. Will do. Then, it becomes difficult to identify and control the direction and magnitude of the elastic contraction force acting on the optical unit at the plurality of points, and as a result, the intraocular lens for suppressing the rotation of the intraocular lens in the eyeball. It is difficult to determine the configuration.

  Therefore, in the present invention, by adopting a support part of a type that is coupled to the optical part only at the coupling part as the support part, the point of action of the elastic contraction force on the optical part is limited to the coupling point only. Can do. If it does so, it will become easier to grasp | ascertain the direction of the elastic contraction force which acts on an optical part, a magnitude | size, and a place. As a result, the design and control of the configuration for suppressing the rotation of the intraocular lens in the eyeball after insertion becomes easier. Thereby, it can suppress more reliably that an intraocular lens rotates in an eyeball after insertion.

The support unit supports the intraocular lens in the eyeball by the support point in contact with the eyeball tissue in the radial direction of the intraocular lens,
The other part of the support point in the support part may be configured not to contact the eyeball tissue in the radial direction of the intraocular lens.

  In the present invention, in a state after being inserted into the eyeball, a support point having a maximum radial distance from the center of the optical part among the support parts of the intraocular lens, the support part, and the optical part Are coupled to each other, and the center of the optical part is arranged in a substantially straight line. Thereby, it is possible to suppress the elastic contraction force in the circumferential direction of the optical part that acts on the coupling point as described above.

  In addition, when the intraocular lens is actually inserted into the eyeball, the elastic contraction force acting on the coupling point is affected when other portions of the support point in the support portion come into contact with the eyeball tissue in the radial direction of the intraocular lens. The direction and size may also change. If it does so, there exists a possibility that it may become difficult to specify and control appropriately the direction of the elastic contraction force which acts on a connection point. Therefore, in the present invention, other portions of the support point in the support portion are configured not to contact the eyeball tissue in the radial direction of the intraocular lens. Thereby, it can suppress that the magnitude | size and direction of the elastic contraction force which act on a connection point change from assumption significantly. As a result, it can suppress more reliably that an intraocular lens rotates in an eyeball after insertion.

In the present invention,
An optical unit having optical performance that can replace the crystalline lens in the eyeball;
An intraocular lens having a plurality of support portions provided in a form extending on an outer peripheral side of the optical portion and supporting the optical portion within an eyeball,
In the state before the intraocular lens is inserted into the lens capsule, a support point having a maximum radial distance from the center of the optical unit among the support units, and the support unit and the optical unit are You may make it comprise so that the coupling | bonding point which is a coupling | bonding point and the center of the said optical part may be located in a substantially linear form.

  That is, in a state before the intraocular lens is inserted into the capsular bag, a support point having a maximum radial distance from the center of the optical unit among the support units, the support unit, and the optical unit, In most cases, the intraocular lens is inserted into the capsular bag so that the coupling point, which is the coupling point, and the center of the optical unit are arranged in a substantially straight line. Even in the state, the support point that is the maximum radial distance from the center of the optical part of the support part, the coupling point that is the point where the support part and the optical part are coupled, and the center of the optical part are approximately It can be configured to be arranged in a straight line.

  More specifically, it is assumed that the maximum distance of the support part of the intraocular lens, that is, the distance between both support points is set to, for example, about 11 to 13 mm before the intraocular lens is inserted into the lens capsule. On the other hand, the size of the human lens capsule is known to be about 9 mm to 12 mm in adults, although it varies slightly depending on individual differences. In such a case, when the above-mentioned intraocular lens is inserted into the crystalline lens capsule, the support portion is pressed against the capsule and elastically deformed inward, and accordingly, the position of the support point shifts in the support portion (shifts in the respective root directions). ) However, if the maximum distance of the support part before being inserted into the capsular bag is appropriately selected according to the size of the sac, the amount of deviation can be made small. Then, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is the force acting on the coupling unit in the direction of rotating the optical unit. It is kept within a sufficiently small range. Therefore, even if the intraocular lens is in a state after being inserted into the crystalline lens capsule, it is considered that a sufficient rotation suppression effect can be obtained practically.

  Therefore, in the present invention, in the state before the intraocular lens is inserted into the capsular bag, a support point having a maximum radial distance from the center of the optical part among the support parts, and the support part In addition, the intraocular lens may be configured such that a coupling point, which is a point where the optical unit and the optical unit are coupled, and a center of the optical unit are arranged in a substantially straight line. Also in this state, in the state after the intraocular lens is inserted into the capsular bag, out of the elastic contraction force that acts on the coupling portion when the capsular bag contracts for focus adjustment, the direction of rotating the optical unit. The component can be made sufficiently small, and the rotation after the intraocular lens is inserted into the eyeball can be suppressed. Of course, the amount of deviation is predicted in advance, and when inserted into the capsular bag, the support point, the coupling point, and the center of the optical part are aligned in a substantially straight line, respectively, in a direction opposite to the direction shifted at the time of insertion. It is also possible to configure the intraocular lens by arranging the points slightly shifted from the straight line.

  In the present invention, the support portion may have no inflection point in a range from the coupling point to the support point before the intraocular lens is inserted into the lens capsule. Good.

  That is, if the support part does not have an inflection point in the range from the coupling point to the support point before the intraocular lens is inserted into the lens capsule, Even in a state where the inner lens is inserted into the lens capsule, the support portion can be made to have no inflection point in the range from the coupling point to the support point.

  Therefore, in the present invention, the support portion does not have an inflection point in a range from the coupling point to the support point before the intraocular lens is inserted into the lens capsule. Thus, the support point, the coupling point, and the center of the optical unit can be arranged substantially linearly in a state after the intraocular lens is inserted into the lens capsule. As a result, even if the lens capsule contracts, it becomes possible to make it difficult for the elastic contraction force in the direction of rotating the optical section to act on the coupling section.

  Further, in the present invention, an angle formed by a straight line connecting the support point and the center of the optical unit and a straight line connecting the coupling point and the center of the optical unit is such that the intraocular lens is inserted into the lens capsule. In a state before being performed, the angle may be 14.4 degrees or less.

  That is, the angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is 14.4 in the state before the intraocular lens is inserted into the lens capsule. The angle between the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is determined by the intraocular lens for most patients. Even in a state of being inserted into the lens capsule, it can be made 14.4 degrees or less.

  Therefore, in the present invention, an angle formed by a straight line connecting the support point and the center of the optical unit and a straight line connecting the coupling point and the center of the optical unit is such that the intraocular lens is inserted into the lens capsule. By setting the angle to 14.4 degrees or less in the state before being performed, it is possible to sufficiently suppress the intraocular lens from rotating in the eyeball after insertion.

  The means for solving the above-described problems of the present invention can be used in combination as much as possible.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the intraocular lens arrange | positioned in an eyeball as a lens replaced with a crystalline lens rotates after arrangement | positioning.

It is a figure which shows schematic structure in the state by which the conventional intraocular lens is arrange | positioned in the lens capsule. It is a figure for demonstrating the effect | action of an elastic contractile force when an eyeball changes from a far vision state to a near vision state in the state where the intraocular lens is arrange | positioned in a crystalline lens capsule. It is a figure which shows the state in the moment when the elastic contraction force of the lens capsule acted on the intraocular lens. It is a figure for demonstrating the specific example of the rotation prevention countermeasure in the Example of this invention. It is a figure which shows the support part shape of the intraocular lens by which the countermeasure against rotation prevention in the Example of this invention was carried out. It is a figure which shows the result of the conventional product in the effect confirmation experiment of the rotation prevention measure in the Example of this invention. It is a figure which shows the result of the intraocular lens in which the rotation prevention countermeasure was completed in the effect confirmation experiment of the rotation prevention countermeasure in the Example of this invention. It is a figure at the time of applying this invention to a one-piece type intraocular lens. It is a figure at the time of applying this invention to the intraocular lens provided with three or more support parts.

  Embodiments of the present invention will be described below with reference to the drawings.

<Example 1>
FIG. 1 shows an appearance of a conventional intraocular lens 1 in a state where the intraocular lens 1 is disposed in a crystalline lens capsule. FIG. 1A is a plan view of the intraocular lens 1, and FIG. 1B is a side view. As shown in FIG. 1, a conventional intraocular lens 1 is provided in a lens main body 1a as an optical unit that functions as a lens in the eyeball, and holds the lens main body 1a in the eyeball. For this reason, it is formed from two support portions 1b and 1b having a beard shape. The lens body 1a is made of a flexible resin material. In this embodiment, the points where the lens body 1a and the support portions 1b and 1b are coupled are defined as coupling points 1c and 1c. Further, in the support portions 1b and 1b, points having the maximum distance from the center of the lens body 1a are defined as support points 1d and 1d.

  The material of the intraocular lens 1 is not particularly limited. Theoretically, thermoplastic resins such as styrene resins, acrylic resins, aromatic polycarbonate resins, amorphous polyolefin resins, polyamide resins, aromatic polyester resins, polyphenylene ether resins and polyarylene sulfide resins, or phenol resins Synthetic resins of non-thermoplastic resins such as urea resin, melamine resin, unsaturated polyester, epoxy resin, diallyl phthalate resin, polyurethane resin, silicon resin, polyimide resin, and inorganic amorphous materials such as glass and silicone can also be used It is desirable that it be formed of a flexible soft material.

  When the intraocular lens 1 as described above is applied to a patient having corneal astigmatism, an astigmatism correction lens called a toric lens may be used as the optical unit 1a. When the intraocular lens 1 in this case is inserted into the eyeball of a patient with corneal astigmatism, the direction of the astigmatic axis of the patient's cornea and the direction of the toric axis of the intraocular lens 1 must be matched.

  In this regard, in the operation of inserting the intraocular lens 1 into the eyeball, generally, the direction in which the intraocular lens 1 can be attached to an insertion instrument (not shown) used for the insertion operation is determined (usually two support portions). When the lens is inserted into the eyeball, the directions of the support portions 1b and 1b are directed to a certain direction with respect to the eyeball. ing. Therefore, in order to match the astigmatic axis direction of the cornea with the toric axis direction of the intraocular lens 1, the intraocular lens 1 is rotated from the state in which the intraocular lens 1 is inserted into the eyeball, and the direction of the toric axis. Must be adjusted. And it is necessary to hold | maintain the adjusted state in an eyeball.

  However, in reality, after the intraocular lens is inserted into the eyeball, the toric axis is likely to be displaced because the intraocular lens is not sufficiently fixed by the crystalline lens capsule until the lens capsule is completely contracted. Since cataract surgery is often performed as day surgery, there is a case where some force acts on the intraocular lens in the course of normal life and the direction of the toric axis of the intraocular lens is shifted. As a result, even if an intraocular lens insertion operation is performed, there is a possibility that desired visual acuity recovery cannot be realized.

  Here, the reason why the intraocular lens 1 rotates after the intraocular lens 1 is inserted into the eyeball will be examined. Specifically, the possibility that a contact force as an external force acts on the intraocular lens 1 inserted into the eyeball will be examined.

  For example, when a person looks close, the lens becomes thicker and focuses on the near point by increasing the refractive power. FIG. 2 shows a conceptual diagram when the Helmholtz theory is applied as this mechanism. FIG. 2A shows a far vision state. FIG. 2B shows a near vision state. As shown in FIG. 2 (a), the ciliary muscle M relaxes and expands in the far vision state, and the Chin zonule Z is pulled outward. The elastic contraction force F1 of the lens capsule C, the tension σ1 of the chin band Z, and the drag γ of the ciliary muscle M are balanced. Therefore, in the far vision state, the elastic contraction force as the contact force does not act on the intraocular lens 1.

  On the other hand, when trying to shift from the far vision state to the near vision state, as shown in FIG. 2B, the ciliary muscle M contracts due to tension and contraction force τ acts. Therefore, the tension of the chin strap Z changes to σ2, and as a result, the elastic contraction force F2 acts on the support portions 1b and 1b of the intraocular lens 1 from the lens capsule C.

  Next, the conditions under which the intraocular lens 1 rotates when the elastic contraction force F2 acts on the support portions 1b and 1b from the lens capsule C will be examined. FIG. 3 shows a state at the moment when the elastic contraction force F2 of the sac is applied. As can be seen from FIG. 3, in this embodiment, the coupling points 1c and 1c and the center O of the lens body 1b exist on a straight line. The support points 1d and 1d are substantially in point contact with the inner surface of the lens capsule C, and the support points 1d and 1d and the center O of the lens body 1a are also present on a straight line. Therefore, it can be said that the intraocular lens 1 before the elastic contraction force F2 is applied is equivalent to a state where the center O of the lens body 1a is pin-joined (translational constraint / rotation free condition). In addition, since the elastic contraction force F2 of the lens capsule C as an external force is generated isotropically (symmetrically), the pin joint state is maintained even when an external force is applied.

  Here, for each support portion 1b, 1b, an angle formed by a straight line connecting the support points 1d, 1d and the center O of the lens body 1a and a straight line connecting the connection points 1c, 1c and the center O of the lens body 1a. Is θ. In the present embodiment, since the two support portions 1b and 1b are configured to be point-symmetric with respect to the center O of the lens body 1a at intervals of 180 °, the support point 1d and the center O of the lens body 1a Is the angle formed by the straight line connecting the connecting point 1c and the straight line connecting the center O of the lens body 1a, and θ is the connecting line between the two supporting points 1d and the two connecting points 1c. It corresponds to the angle formed by the straight line. Therefore, θ in the present embodiment can be restated as an angle formed by a straight line connecting two support points 1d and a straight line connecting two coupling points 1c.

As described above, even when the elastic contraction force F2 is applied, the above-described pin joint state is maintained. Therefore, when the elastic contraction force F2 is applied to the support points 1d and 1d in FIG. 3, the support portions 1b and 1b are deformed. Further, the rotational movement of the lens body 1a is started. At that time, the elastic contraction force F2 acting on the support points 1d and 1d acts on the coupling points 1c and 1c as they are. Here, at the coupling points 1c and 1c, the normal direction component Fn and the tangential direction component Ft of the lens main body 1a of the applied elastic contraction force F2 are described as in the equations (1) and (2), respectively. It is possible.
Fn = F2 · COSθ (1)
Ft = F2 · SINθ (2)

As is apparent from FIG. 3, Fn acts in the opposite direction with respect to both coupling points 1c and 1c, and thus cancels out as a result. On the other hand, both Ft acting on both coupling points 1c and 1c cause a moment in the clockwise direction in the lens body 1a. The moment generated at this time can be described as follows.
Mcw = Ft · (d / 2) (3)
Here, d is the diameter of the lens body 1a.

In the system shown in FIG. 3, the static frictional force f acts at the support points 1d and 1d that are in contact with the inner surface of the lens capsule C. The maximum static friction force fmax can be described as follows from Coulomb's law of friction.
fmax = μ · T (4)
Here, μ is a coefficient of static friction between the support portions 1b and 1b and the inner surface of the lens capsule C, and T is an elastic force of the support portions 1b and 1b acting on the inner surface of the lens capsule C that is generated in a balanced state. is there.

Since fmax has a turning radius (inner radius of the lens capsule C) D / 2, a counterclockwise moment Mcccw is generated. This moment Mccw can be described as follows.
Mccw = fmax (D / 2) (5)

Regarding the above formulas (3) and (5), the intraocular lens 1 rotates when the counterclockwise moment Mcccw is smaller than the clockwise moment Mcw. That is, the conditions for the rotation of the intraocular lens 1 are as follows.
Mcw> Mccw (6)
From equations (3), (5), (6)
Ft · (d / 2)> fmax · (D / 2) (7)
It becomes.
Then, from the equations (2), (4), (7),
F2 · (d / 2) · sinθ> μ · T · (D / 2) (8)
Solving for μ μ <(F2 · d / T · D) · sinθ (9)
It becomes.

From equation (9), the following measures can be considered to make it difficult for the intraocular lens 1 to rotate within the eyeball.
1. The static friction coefficient μ between the support portion 1b and the inner surface of the lens capsule C is increased.
2. The elastic contraction force F2 of the lens capsule C is reduced.
3. The diameter d of the lens body 1a is reduced.
4). The elastic force T of the support portions 1b and 1b is increased.
5). The radius D of the lens capsule C is increased.
6). An angle θ formed by a straight line connecting the support point 1d and the center O of the lens body 1a and a straight line connecting the coupling point 1c and the center O of the lens body 1a is brought close to 0 ° or 180 ° (sin θ is reduced). .)

  Among the above, the measures 1, 2, and 5 are based on the characteristics of the lens capsule C of the patient, and thus cannot be adopted as a design measure for the intraocular lens 1. Further, the third countermeasure is difficult to implement because it affects the optical performance of the intraocular lens 1. Furthermore, since measures 1 and 4 are related to the material of the support portion 1b, it is difficult to consider the biocompatibility of the support portion material. Therefore, in this embodiment, 6 is adopted as the most realistic countermeasure among the above-described countermeasures 1 to 6.

  FIG. 4 is a diagram for explaining a specific example of the above six measures (hereinafter also referred to as rotation prevention measures). FIG. 4A shows a conventional intraocular lens. In FIG. 4B, an angle θ formed by a straight line connecting the support point 1d and the center O of the lens body 1a and a straight line connecting the coupling point 1c and the center O of the lens body 1a is made close to 0 °. It is an intraocular lens. In FIG. 4C, the angle θ formed by the straight line connecting the support point 1d and the center O of the lens body 1a and the straight line connecting the coupling point 1c and the center O of the lens body 1a is close to 180 °. It is an intraocular lens. As can be seen from FIGS. 4B and 4C, the conditions for making it difficult to rotate after the intraocular lens is placed in the eyeball are the support point 1d and the coupling point 1c for each support portion 1b. In other words, it can be configured that the lens body 1 and the center O of the lens body 1 are substantially in a straight line (aligned in a substantially straight line).

  In FIG. 5, the example of schematic structure of the conventional intraocular lens 1 and the intraocular lens incorporating the rotation prevention countermeasure in a present Example is shown. FIG. 5A shows a conventional intraocular lens 1 and FIG. 5B shows an intraocular lens 10 with anti-rotation measures. In the intraocular lens 10, the lens body 1 a is exactly the same as the conventional intraocular lens 1. The shapes of the support portions 10 b and 10 b are changed from the support portions 1 b and 1 b of the conventional intraocular lens 1. In this embodiment, the angle θ formed by the straight line connecting the support point 10d and the center O of the lens body 1a and the straight line connecting the coupling point 10c and the center O of the lens body 1a is 14.4 °, It was greatly reduced from 70 °. Thereby, even if the elastic contraction force F2 acts on the support points 10d and 10d, it is possible to suppress the force from acting on the coupling points 10c and 10c in the circumferential direction of the lens body 10a, and a rotational moment is generated in the intraocular lens 10. This can be suppressed.

  In the present embodiment, the support portions 10b and 10b are open-loop support portions, and the lens body 1a and the support portions 10b and 10b are coupled only at the coupling points 10c and 10c. The support portions 10b and 10b are extended from the coupling portions 10c and 10c to the outer peripheral portion of the optical portion 1a, and do not have inflection points in the range from the coupling points 10c and 10c to the support points 10b and 10b. . That is, the support portions 10b and 10b are designed to partially bend in a counterclockwise direction in the figure with a large curvature compared to the support portions 1b and 1b. Designed in the same way as 1b. Further, in the support portions 10b and 10b, the lens capsule C is not contacted in the radial direction of the optical portion 1a at points other than the support points 10d and 10d where the distance from the center of the lens body 1a is maximum. .

  FIG. 5 shows a schematic configuration of the conventional intraocular lens 1 and the intraocular lens incorporating the anti-rotation measure in this embodiment before the intraocular lens is inserted into the lens capsule. It is an example. In this regard, if the size of the capsular bag of the patient's eye is within the range of normal variation, the change in θ can be ignored even after the intraocular lens is inserted into the capsular bag. I know it is a thing. In addition, there is no change before and after the intraocular lens is inserted into the capsular bag in that the support portions 10b and 10b do not have an inflection point in the range from the coupling points 10c and 10c to the support points 10b and 10b. I know that. Therefore, in the state before the insertion of the intraocular lens into the lens capsule, the shape of the intraocular lens is set as shown in FIG. 5B, so that the intraocular lens 10 is rotated in the eyeball. Can be sufficiently suppressed. This also applies to the countermeasure example shown in FIG. 4 and the following description in this specification.

  For example, the countermeasure shown in FIG. 4C will be described in detail. The distance between the support points 1d of the two support portions 1b of the intraocular lens before the intraocular lens is inserted into the lens capsule. For example, 11 to 13 mm. On the other hand, the size of the human lens capsule is known to be about 9 mm to 12 mm in adults, although it varies slightly depending on individual differences. In such a case, when the above intraocular lens is inserted into the capsular bag, the support portion 1b is pressed against the sac and elastically deformed inward, and the position of the support point 1d is shifted in the support portion 1b (accordingly, each root). It can be considered that the direction is shifted.

  However, for example, when the distance between the two support points 1d of the intraocular lens before being inserted into the lens capsule is 13 mm and the size of the inserted lens capsule is 12 mm, If the distance between the two support points 1d of the intraocular lens before being inserted is 11 mm and the size of the inserted lens capsule is 9 mm, the distance before and after being inserted into the lens capsule It has been found that the change in θ is sufficiently small, and even in such a case, a sufficient rotation suppression effect can be obtained.

  Next, before being inserted into the lens capsule, the distance between the two support points 1d of the intraocular lens is 13 mm, and the size difference of the lens capsule into which the intraocular lens is inserted is 9 mm. Consider the case where the difference between the distance between the two support points 1d before insertion and the size of the lens capsule is large. In such a case, the change in θ before and after insertion of the intraocular lens into the crystalline lens capsule is large, and it may be difficult to obtain a sufficient rotation suppression effect. For this, a plurality of intraocular lenses are prepared in which the distance between the two support points 1d before insertion is changed, the distance between the two support points 1d of the intraocular lens, and the intraocular lens A lens capsule in which the difference in size of the lens capsule into which the lens is inserted is sufficiently small may be selected and inserted. Alternatively, the direction of deviation at the time of insertion is predicted so that the amount of change in θ is predicted in advance and the support point 1d, the coupling point 1c, and the center O of the optical part are aligned in a substantially straight line when inserted in the lens capsule. It is also possible to configure an intraocular lens by arranging each point in the opposite direction with a slight shift from the straight line.

Next, an experiment for confirming the effect of the anti-rotation measure in this embodiment and the result thereof will be described. In this embodiment, in order to reproduce an operation similar to the human focus adjustment operation, a compression load tester and an experimental jig that looks like a lens capsule C are used, and the conventional intraocular lens 1 and the rotation in this embodiment are used. The intraocular lens 10 that has been subjected to the prevention measures was repeatedly subjected to a compressive motion at a distance between the support points 10d and 10d corresponding to the contraction operation of the lens capsule C. The experimental conditions are shown in Table 1.

  That is, in this experiment, the time required for the near vision from the far vision of the human was set to 1 second. Moreover, the amount of compression in the radial direction at that time was assumed to be 1 mm. Furthermore, the compression speed was determined to be 60 (mm / min). In addition, it was assumed that the patient would be in a near vision state such as a newspaper or reading within 24 hours after the operation. As a measuring method, photographs of the intraocular lens were taken at the time of compression and release in each compression operation, and the change from the initial state of the angle of the straight line connecting the coupling point and the center of the lens body was measured from the image data.

The results are shown in FIGS. 6 and 7 and Table 2. FIG. 6 shows the result of the conventional intraocular lens 1, and FIG. 7 shows the result of the intraocular lens 10 with the anti-rotation measure taken in this embodiment.

  As shown in FIGS. 6 and 7 and Table 2, the conventional intraocular lens 1 was confirmed to rotate by 5 ° after three compression motions. On the other hand, the intraocular lens 10 with anti-rotation measures in this example did not rotate at all after three compression movements.

  As described above, in this embodiment, the angle θ formed by the straight line connecting the support point of the intraocular lens and the center of the lens body and the straight line connecting the connection point and the center of the lens body is 14. It became clear that the rotation of the intraocular lens within the eyeball can be suppressed after being inserted and arranged in the eyeball by setting the angle to 4 °. In the above embodiment, the angle θ formed by the straight line connecting the support point of the intraocular lens and the center of the lens body and the straight line connecting the coupling point and the center of the lens body is 14.4 °. However, it is natural that θ in the present invention is not limited to this.

  First, from the above results, if θ is an angle of 14.4 ° or less and 0 ° or more, the effect of this embodiment or more can be expected. Similarly, even if θ is an angle of 165.6 ° (180 ° -14.4 °) or more and 180 ° or less, it is considered that the effect of this embodiment or more can be expected. Further, in the conventional intraocular lens 1, θ is 70 °. Therefore, if the angle is smaller than 70 ° or larger than 110 ° (180 ° -70 °), the improvement is compared with the conventional product. Since it should be seen, such an angle may be used. Of course, in principle, the effect will be greatest if θ is 0 ° or 180 °.

  In the above-described embodiments, the lens body that is an optical part and the support part are formed separately, and an example in which the present invention is applied to a three-piece intraocular lens that is bonded by a method such as adhesion or press fitting has been described. The present invention can also be applied to a one-piece intraocular lens in which an optical part and a support part are integrally formed. FIG. 8 shows a schematic configuration when the present invention is applied to a one-piece type intraocular lens 15. Also in this case, the angle θ formed by the straight line connecting the support points 15d and 15d and the center O of the lens body 1a and the straight line connecting the coupling points 15c and 15c and the center O of the lens body 1a is 14.4. By setting the angle, it is possible to obtain the same effect as that of the three-piece intraocular lens 10.

  In the above-described embodiment, an example in which a pair of support portions is provided at an interval of 180 ° on the lens body that is an optical portion has been described. However, the present invention can also be applied to other types of intraocular lenses. FIG. 9 shows an example in which three support portions 20b are provided at intervals of 120 ° on the lens body 20a which is an optical portion. Even in this case, for each support portion 20b, the angle between the straight line connecting the support point 20d and the center O of the lens body 20a and the straight line connecting the coupling point 20c and the center O of the lens body 20a is 0 ° or 180 °. By making the angle close to ° (each θ is 14.4 ° in FIG. 9), it is possible to suppress the rotation of the intraocular lens 20 after being inserted and arranged in the eyeball. In other words, even in an intraocular lens provided with three or more support portions, each support portion is configured so that the support point, the coupling point, and the center of the optical portion are substantially in a straight line. Rotation in the eyeball can be suppressed.

  The intraocular lens shown in the above embodiment has a point-symmetric configuration with respect to the center O of the lens body. Accordingly, the support point, the connection point, and the angle formed by the straight line connecting the support point and the center O of the lens body and the straight line connecting the connection point and the center of the lens body are only for some support parts. Although the code | symbol may be described, it is the common structure also about the support part in which the code | symbol is not described.

  In the above-described embodiment, the center O of the lens body that is the optical unit indicates the center of the lens body that is circular. If the lens body is not circular, the center O indicates the center of rotation of the lens body. For example, when the lens body is elliptical, it may be an intermediate point between two elliptical centers. Further, when the lens body is oval, it may be an intermediate point between the centers of the arc portions at both ends. Further, when the lens body is rectangular, it may be an intersection of diagonal lines.

DESCRIPTION OF SYMBOLS 1, 10, 15, 20 ... Intraocular lens 1a, 10a, 15a, 20a ... Lens body 1b, 10b, 15b, 20b ... Support part 1c, 10c, 15c, 20c ... Connection point 1d 10d, 15d, 20d ... support point C ... lens capsule F2 ... elastic contraction force M ... ciliary muscle Z ... chin band

Claims (8)

An optical unit having optical performance that can replace the crystalline lens in the eyeball;
An intraocular lens having a plurality of support portions provided in a form extending on an outer peripheral side of the optical portion and supporting the optical portion within an eyeball,
In the state where the intraocular lens is inserted into the capsular bag, a support point having a maximum radial distance from the center of the optical unit, and the support unit and the optical unit are combined. An intraocular lens, wherein a coupling point that is a point and a center of the optical unit are arranged in a substantially straight line.   2. The intraocular device according to claim 1, wherein the support portion does not have an inflection point in a range from the coupling point to the support point in a state where the intraocular lens is inserted into the lens capsule. lens.   The angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is 14.4 in a state where the intraocular lens is inserted into the lens capsule. The intraocular lens according to claim 1, wherein the intraocular lens is less than or equal to a degree.   4. The intraocular lens according to claim 1, wherein each of the plurality of support units is coupled to the optical unit only at the coupling point. 5. The support unit supports the intraocular lens in the eyeball by the support point in contact with the eyeball tissue in the radial direction of the intraocular lens,
The other part of the support point in the support part is configured not to come into contact with the eyeball tissue in the radial direction of the intraocular lens. Intraocular lens. An optical unit having optical performance that can replace the crystalline lens in the eyeball;
An intraocular lens having a plurality of support portions provided in a form extending on an outer peripheral side of the optical portion and supporting the optical portion within an eyeball,
In the state before the intraocular lens is inserted into the lens capsule, a support point having a maximum radial distance from the center of the optical unit among the support units, and the support unit and the optical unit are An intraocular lens characterized in that a coupling point, which is a coupling point, and a center of the optical unit are arranged in a substantially straight line.   The said support part does not have an inflection point in the range from the said connection point to the said support point in the state before the said intraocular lens is inserted in a lens capsule. Intraocular lens.   The angle formed by the straight line connecting the support point and the center of the optical unit and the straight line connecting the coupling point and the center of the optical unit is the state before the intraocular lens is inserted into the lens capsule. The intraocular lens according to claim 6 or 7, wherein the angle is 14.4 degrees or less.

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